SERIES 40 ENGINE OPERATOR'S GUIDE
Dropout
Excessive amounts of some inhibitors
in the coolant can cause a gel or
crystalline deposit that reduces heat
transfer and coolant
fl
ow. The deposit,
called “dropout,” takes the color of
the coolant when wet, but appears as a
white or gray powder when dry. It can
pick up solid particles in the coolant
and become gritty, causing excessive
wear of water pump seals and other
cooling system components.
To avoid injury when using
caustic cleaning agents, follow
the chemical manufacturers
usage, disposal, and safety
instructions.
The wet gel can be removed by
using a non-acid (alkali) type
heavy-duty cleaner, such as Detroit
Diesel
Power Cool
On-Line Cleaner
(sodium nitrite/sodium tetraborate).
Refer to section
POWER COOL
COOLING SYSTEM CLEANERS
for part numbers.
NOTE:
If the gel is allowed to dry, it is
necessary to disassemble the
engine and clean it with a caustic
solution or physically clean individual
components.
Coolant Extender Inhibitor
Additive for “OAT” Coolant
The inhibitors in OAT coolant must
also be maintained, but less often
than traditional SCA-type coolants.
A portable test is available to test the
levels of OAT inhibitors in coolant.
Where this is not used,
fl
eet testing
has determined that a OAT coolant
extender package should be added to
the coolant at 300,000 miles (480,000
km), two (2) years, or 5,000 hours,
whichever comes
fi
rst. The proper
maintenance dosages for all OAT
coolants are listed in Table 29 ,
re
fl
ecting 0.6% by volume extender.
This dosage should be added to the
water-only and the glycol systems at
the same interval.
The proper application of extender to
OAT coolant will provide:
□
pH Control
□
Restored inhibitor levels to prevent
corrosion
□
Cavitation protection to protect
wet sleeve cylinder liners
NOTE:
Do not use traditional SCAs in
OAT coolant, and do not use
OAT extender in traditional coolant.
OAT Coolant Drain Interval —
A properly maintained OAT-inhibited
coolant will last 600,000 miles
All information subject to change without notice.
(Rev. May 2004)
101
DDC-SVC-MAN-0057 0305
Copyright © 2003 DETROIT DIESEL CORPORATION
